Secondary battery

Abstract

To provide a secondary battery capable of suppressing breakage of an electrode body.SOLUTION: A rechargeable battery includes an assembly 100 having at least one negative-electrode tab 110N formed at a first end 111 and at least one positive-electrode tab 110P formed at a second end 112, a housing that houses the assembly 100, and negative-electrode and positive-electrode terminals 520 and 620 provided in the housing. The housing includes a tubular main body portion 210, a first sealing body 510, and a second sealing body 610, the negative electrode terminals 520 are provided on the first sealing body 510, the positive electrode terminals 620 are provided on the second sealing body 610, the one or more negative electrode tabs 110N are electrically connected to the negative electrode terminals 520, and the one or more positive electrode tabs 110P are electrically connected to the positive electrode terminals 620. One of the one or more negative electrode tab 110N and the one or more positive electrode tab 110P is longer in length than the other of the one or more negative electrode tab 110N and the one or more positive electrode tab 110P.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a secondary battery, and more particularly to a secondary battery mounted on a vehicle. [Background technology]

[0002] As a conventional secondary battery, U.S. Patent Application Publication No. 2022 / 0302533 (Patent Document 1) discloses a configuration in which a housing that houses an electrode body has a case body that is open on both longitudinal sides, and each opening of the case body is closed with a cover member provided with an external terminal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2022 / 0302533 Summary of the Invention [Problem to be solved by the invention]

[0004] In the secondary battery disclosed in Patent Document 1, after the external terminal and the current collector are assembled to the lid member in advance to form a lid assembly, the electrode tab provided on the electrode body is fixed to the current collector of the lid assembly, and then the opening of the case body is closed with the lid assembly in a state where the electrode tab is fixed to the current collector.

[0005] Specifically, first, an electrode tab (e.g., a positive electrode tab) of the electrode body is connected to a current collector of the lid assembly on one side in the longitudinal direction, and the opening of the case body is closed with the lid assembly, then, an electrode tab (e.g., a negative electrode tab) of the electrode body is connected to a current collector of the lid assembly on the other side in the longitudinal direction, and the opening of the case body is closed with the lid assembly.

[0006] Depending on the state of fixation between the current collector and the electrode tab on one side in the longitudinal direction, there is a concern that the electrode tab may be pulled and fixed to the current collector on the other side in the longitudinal direction. In this case, if no measures are taken, the entire electrode body may be pulled, which may result in damage to the electrode body.

[0007] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a secondary battery capable of suppressing breakage of an electrode assembly. [Means for solving the problem]

[0008] A secondary battery according to the present disclosure includes an electrode assembly having a first end located on one side in a first direction and a second end located on the other side in the first direction, with one or more negative electrode tabs formed at the first end and one or more positive electrode tabs formed at the second end, a housing that houses the electrode assembly, and a negative electrode terminal and a positive electrode terminal provided on the housing. The housing includes a cylindrical main body portion having a first opening on the one side in the first direction and a second opening on the other side in the first direction, a first sealing body that closes the first opening, and a second sealing body that closes the second opening. The negative electrode terminal is provided on the first sealing body. The positive electrode terminal is provided on the second sealing body. The one or more negative electrode tabs are electrically connected to the negative electrode terminal. The one or more positive electrode tabs are electrically connected to the positive electrode terminal. One of the one or more negative electrode tabs and the one or more positive electrode tabs has a length greater than the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

[0009] According to the above configuration, one of the positive electrode tab and the negative electrode tab is electrically connected to one of the positive electrode terminal and the negative electrode terminal, which has the same polarity as the one of the electrode tabs. The other of the positive electrode tab and the negative electrode tab is electrically connected to the other of the positive electrode terminal and the negative electrode terminal. The one external terminal is provided on one of the first sealing body and the second sealing body. The other external terminal is provided on the other of the first sealing body and the second sealing body. The one sealing body closes one of the first opening and the second opening. The other sealing body closes the other of the first opening and the second opening.

[0010] When assembling the secondary battery, the other electrode tab is electrically connected to the other external terminal and the other opening of the main body is closed with the other sealing body, and then the one electrode tab is electrically connected to the one external terminal and the one opening of the main body is closed with the one sealing body. In this case, as described above, the one electrode tab is longer than the other electrode tab. This allows the one sealing body to be assembled to the one opening while adjusting the degree of slack in the one electrode tab. As a result, the force applied to the electrode body can be reduced, and damage to the electrode body can be prevented.

[0011] In the secondary battery based on the present disclosure, one of the one or more negative electrode tabs and the one or more positive electrode tabs may sag more than the other of the one or more negative electrode tabs and the one or more positive electrode tabs.

[0012] According to the above configuration, one electrode tab sags more than the other electrode tab, so that the force applied to the electrode body can be more reliably suppressed.

[0013] In the secondary battery according to the present disclosure, the main body has a first wall and a second wall that face each other in a second direction perpendicular to the first direction. The first wall is located on one side of the second direction. The second wall is located on the other side of the second direction. The electrode body has a third end located on the one side of the second direction and a fourth end located on the other side of the second direction. In this case, one of the one or more negative electrode tabs and the one or more positive electrode tabs may include a sagging portion that is closer to the first wall than the third end, or a sagging portion that is closer to the second wall than the fourth end.

[0014] According to the above configuration, it is possible to secure a large margin for adjusting the degree of slack in one of the electrode tabs, thereby enabling stable electrical connection between the electrode body and the positive and negative electrode terminals.

[0015] In the secondary battery based on the present disclosure, the other of the one or more negative electrode tabs and the one or more positive electrode tabs may be arranged in the second direction so as not to protrude from the third end toward the first wall portion, and so as not to protrude from the fourth end toward the second wall portion.

[0016] According to the above configuration, the degree of slack in the other tab can be reduced, and contact between the other tab and the housing can be suppressed.

[0017] The secondary battery based on the present disclosure may further include an insulating member disposed between the casing and a sagging portion of one of the one or more negative electrode tabs and the one or more positive electrode tabs, and insulating the sagging portion from the casing.

[0018] According to the above configuration, the insulating member insulates the sagging portion from the housing, thereby preventing electrical conduction between one of the electrode tabs and the housing. [Effects of the Invention]

[0019] According to the present disclosure, a secondary battery capable of suppressing breakage of the electrode assembly can be provided. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view of a secondary battery according to a first embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a secondary battery according to a first embodiment. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. [Figure 5] 1 is a cross-sectional view of a secondary battery showing a connection state of a positive electrode tab and a negative electrode tab according to Embodiment 1. FIG. [Figure 6] 10 is a cross-sectional view of a secondary battery showing the connection state of a positive electrode tab and a negative electrode tab according to Embodiment 2. FIG. [Figure 7] 10 is a cross-sectional view of a secondary battery showing the connection state of a positive electrode tab and a negative electrode tab according to embodiment 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0022] (Embodiment 1) Fig. 1 is a perspective view of a secondary battery according to embodiment 1. Fig. 2 is an exploded perspective view of the secondary battery according to embodiment 1. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1.

[0023] As shown in FIGS. 1 to 3, the secondary battery 10 according to the first embodiment includes an electrode assembly 100, a housing 200, a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.

[0024] The electrode assembly 100 has a first end 101 located on one side in a first direction, and a second end 102 located on the other side in the first direction. The first direction is a direction parallel to a width direction W described below. A plurality of negative electrode tabs 110N are provided at the first end 101. A plurality of positive electrode tabs 110P are provided at the second end 102.

[0025] The electrode body 100 has a third end 103 located on one side in a second direction perpendicular to the first direction, and a fourth end 104 located on the other side in the second direction. The second direction is parallel to a thickness direction T, which will be described later. The detailed configuration of the electrode body 100 will be described later with reference to FIG. 4.

[0026] The housing 200 has a rectangular parallelepiped shape in which the thickness in the thickness direction T is smaller than the width in the width direction W and the height in the height direction H. The thickness direction T is parallel to the parallel direction in which the positive electrode 110 (see FIG. 4) and the negative electrode 120 (see FIG. 4), which will be described later, are arranged side by side. The width direction W is perpendicular to the thickness direction T. The height direction H is perpendicular to the thickness direction T and the width direction W. The width of the housing 200 in the width direction W is greater than the height of the housing 200 in the height direction H, and the width direction W is the longitudinal direction of the housing 200, and the height direction H is the lateral direction of the housing 200.

[0027] The housing 200 accommodates the electrode assembly 100 and an electrolyte (not shown) therein. The housing 200 includes a main body 210, a first sealing member 510, and a second sealing member 610.

[0028] The main body 210 has a cylindrical shape with a first opening 215 and a second opening 216 provided on both sides in the width direction W. More specifically, the main body 210 has a square cylindrical shape with both sides open in the width direction W. The first opening 215 is provided on one side in the width direction W, and the second opening 216 is provided on the other side in the width direction W. The main body 210 is made of a metal such as aluminum.

[0029] The main body 210 includes a first wall 211 and a second wall 212 that face each other in the thickness direction T, and a third wall 213 and a fourth wall 214 that face each other in the height direction H. The areas of the first wall 211 and the second wall 212 are larger than those of the third wall 213 and the fourth wall 214.

[0030] The first wall portion 211 is disposed opposite the third end 103 of the electrode body 100, and the second wall portion 212 is disposed opposite the fourth end 104 of the electrode body 100. The third wall portion 213 is located on one side (upper side) in the height direction H. The third wall portion 213 connects the ends of the first wall portion 211 and the second wall portion 212 located on one side in the height direction H. The fourth wall portion 214 is located on the other side (lower side) in the height direction H. The fourth wall portion 214 connects the ends of the first wall portion 211 and the second wall portion 212 located on the other side in the height direction H.

[0031] The first sealing member 510 closes the first opening 215. The first sealing member 510 has a flat plate shape. The first sealing member 510 is made of a metal such as aluminum. The first sealing member 510 is fixed to the first opening 215 by, for example, laser welding or the like.

[0032] The second sealing member 610 closes the second opening 216. The second sealing member 610 has a flat plate shape. The second sealing member 610 is made of a metal such as aluminum. The second sealing member 610 is fixed to the second opening 216 by, for example, laser welding.

[0033] Each of the first sealing body 510 and the second sealing body 610 is provided with a pressure release valve 222 and a liquid injection port 224. The pressure release valve 222 is configured to break when the internal pressure of the casing 200 reaches or exceeds a predetermined pressure. When the pressure release valve 222 breaks, gas inside the casing 200 is discharged to the outside of the casing 200, and the internal pressure inside the casing 200 decreases.

[0034] The liquid filling port 224 is sealed with a sealing member 225. The liquid filling port 224 is a through-hole for injecting an electrolyte solution into the housing 200 during the manufacturing process of the secondary battery 10. The liquid filling port 224 is sealed with the sealing member 225. The sealing member 225 is a member that seals the liquid filling port 224 after the electrolyte solution is injected into the housing 200. The sealing member 225 may be, for example, a gas-permeable membrane that is impermeable to liquid but not to gas. In this case, when gas generated during charging is discharged to the outside of the housing 200, the gas can be discharged through the gas-permeable membrane. This eliminates the need to provide a separate gas vent. In addition, the gas-permeable membrane can prevent the electrolyte solution from leaking to the outside of the housing 200. The sealing member 225 is not limited to a gas-permeable membrane, and a resin member, a metal member, or the like can be used as appropriate.

[0035] The first sealing member 510 is provided with a negative electrode member 520, and the second sealing member 610 is provided with a positive electrode member 620.

[0036] The negative electrode member 520 is provided on the outer surface of the first sealing member 510. The negative electrode member 520 functions as a negative electrode terminal. The negative electrode member 520 includes a negative electrode terminal plate 521 and an insulating plate 522.

[0037] Negative electrode terminal plate 521 is formed in a substantially rectangular parallelepiped shape. Negative electrode terminal plate 521 is held by insulating plate 522. Insulating plate 522 is fixed to the outer surface of first sealing body 510. Insulating plate 522 insulates first sealing body 510 from negative electrode terminal plate 521. Negative electrode terminal plate 521 and insulating plate 522 each have a through hole for inserting a cylindrical portion 532, which will be described later.

[0038] The positive electrode member 620 is provided on the outer surface of the second sealing member 610. The positive electrode member 620 functions as a positive electrode terminal. The positive electrode member 620 has a positive electrode terminal plate 621 and a terminal block 622.

[0039] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0040] Terminal block 622 is formed in a rectangular parallelepiped shape. Terminal block 622 is made of a metal (such as iron) different from the metal making up positive electrode terminal plate 621. Terminal block 622 is fixed to the outer surface of second sealing body 610 by welding or the like. Positive electrode terminal plate 621 is fixed to terminal block 622 by welding or the like. Main body 210 and second sealing body 610 are electrically connected to positive electrode terminal plate 621 via terminal block 622, and are charged with the same polarity as positive electrode terminal plate 621. Positive electrode terminal plate 621 and terminal block 622 each have a through hole formed therein for inserting a cylindrical portion 632, which will be described later.

[0041] An insulating plate may be disposed between the positive electrode component 620 and the second sealing member 610, thereby electrically insulating the positive electrode component 620 from the second sealing member 610. In this case, an insulating plate may be disposed instead of the terminal block 622, or an insulating plate may be disposed between the terminal block 622 and the second sealing member 610.

[0042] The secondary battery 10 further includes a negative electrode conductive member 530 and an insulator 560 on the negative electrode member 520 side.

[0043] The negative electrode side conductive member 530 connects the multiple negative electrode tabs 110N and the negative electrode terminal plate 521. The multiple negative electrode tabs 110N are connected to the negative electrode side conductive member 530 in a bundled state by ultrasonic welding or the like. The negative electrode side conductive member 530 includes a plate-shaped portion 531 and a cylindrical portion 532. The plate-shaped portion 531 is approximately parallel to the inner surface of the first sealing body 510. The cylindrical portion 532 extends in a direction parallel to the first direction. The tip of the cylindrical portion 532 penetrates the first sealing body 510, the insulating plate 522, and the negative electrode terminal plate 521, and is crimped to the negative electrode terminal plate 521.

[0044] Insulator 560 is disposed between plate-shaped portion 531 and first sealing body 510, and insulates plate-shaped portion 531 from first sealing body 510. Insulator 560 includes a portion that covers the periphery of the base end side of columnar portion 532, and a portion that is located between plate-shaped portion 531 and the inner surface of first sealing body 510.

[0045] The negative electrode member 520, the first sealing member 510, the negative electrode side conductive member 530, and the insulator 560 are assembled together to form the first lid assembly 50.

[0046] The first lid assembly 50 is fixed to the main body 210 by attaching the first sealing body 510 to the first opening 215 with the multiple negative electrode tabs 110N and the negative electrode side conductive member 530 fixed by welding or the like.

[0047] The secondary battery 10 further includes a positive electrode conductive member 630 and an insulator 660 on the positive electrode member 620 side.

[0048] The positive electrode side conductive member 630 connects the multiple positive electrode tabs 110P and the positive electrode terminal plate 621. The multiple positive electrode tabs 110P are connected to the positive electrode side conductive member 630 in a bundled state by ultrasonic welding or the like. The positive electrode side conductive member 630 includes a plate-shaped portion 631 and a cylindrical portion 632. The plate-shaped portion 631 is approximately parallel to the inner surface of the second sealing body 610. The cylindrical portion 632 extends in a direction parallel to the first direction. The tip of the cylindrical portion 632 penetrates the second sealing body 610, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0049] Insulator 660 is disposed between plate-shaped portion 631 and second sealing body 610, and insulates plate-shaped portion 631 from second sealing body 610. Insulator 660 includes a portion that covers the periphery of the base end side of columnar portion 632, and a portion that is located between plate-shaped portion 631 and the inner surface of second sealing body 610.

[0050] The positive electrode member 620, the second sealing member 610, the positive electrode side conductive member 630, and the insulator 660 are assembled together to form the second lid assembly 60.

[0051] The second lid assembly 60 is fixed to the main body 210 by attaching the second sealing body 610 to the second opening 216 with the multiple positive electrode tabs 110P and the positive electrode side conductive member 630 fixed by welding or the like.

[0052] Fig. 4 is a cross-sectional view taken along line IV-IV shown in Fig. 1. For convenience, Fig. 4 omits the housing 200 of the secondary battery 10 and shows only the electrode assembly 100. Details of the electrode assembly 100 will be described with reference to Fig. 4.

[0053] 4, the electrode assembly 100 includes a plurality of positive electrodes 110, a plurality of negative electrodes 120, and a separator 130. The plurality of positive electrodes 110 and the plurality of negative electrodes 120 are arranged alternately in the thickness direction T while being insulated by the separator 130.

[0054] Each negative electrode 120 is formed in a rectangular shape with the longitudinal direction being the width direction W and the transverse direction being the height direction H. Each negative electrode 120 has a negative electrode current collector foil 122 and a negative electrode active material layer 124 provided on both sides of the negative electrode current collector foil 122. As shown in FIG. 4, the negative electrode current collector foil 122 has a negative electrode tab 110N on which no negative electrode active material layer 124 is provided. The negative electrode tab 110N protrudes toward one side in the width direction W.

[0055] Each positive electrode 110 is formed in a rectangular shape with the lengthwise direction W as the length and the heightwise direction H as the widthwise direction. Each positive electrode 110 has a positive electrode current collector foil 112 and positive electrode active material layers 114 provided on both sides of the positive electrode current collector foil 112 in the thicknesswise direction T. The positive electrode current collector foil 112 has a positive electrode tab 110P on which the positive electrode active material layer 114 is not provided. The positive electrode tab 110P protrudes toward the other side in the widthwise direction W.

[0056] The separator 130 provides insulation between the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ions to pass through. The separator 130 is formed in a zigzag shape.

[0057] The separator 130 has a rectangular shape before being folded in a zigzag shape. The separator 130 is disposed between the positive electrode 110 and the negative electrode 120 while being folded in a zigzag shape. The separator 130 has a plurality of intervening portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0058] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120 that are adjacent to each other in the thickness direction T. In other words, each intervening portion 132a has the function of insulating the positive electrode 110 and the negative electrode 120 from each other. Each intervening portion 132a is formed of a rectangular region.

[0059] Each first folded portion 132b connects one side end in the height direction H of adjacent intervening portions 132a in the thickness direction T so that the positive electrode 110 is located between them. The first folded portion 132b is disposed on one side (above) of the positive electrode 110 in the height direction H.

[0060] Each second folded portion 132c connects the other end portions in the height direction H of the intervening portions 132a that are adjacent to each other in the thickness direction T so that the negative electrode 120 is located therebetween. The second folded portion 132c is disposed on the other side (below) of the negative electrode 120 in the height direction H.

[0061] The outermost covering portion 132d collectively covers each of the first folded portions 132b and each of the second folded portions 132c. More specifically, the outermost covering portion 132d collectively covers all of the positive electrodes 110, all of the negative electrodes 120, all of the intervening portions 132a, all of the first folded portions 132b, and all of the second folded portions 132c while being wound around a central axis parallel to the width direction W. The end 132e of the outermost covering portion 132d is set in a range that does not overlap with the positive electrode active material layer 114 and the negative electrode active material layer 124 in the thickness direction T. In this embodiment, the end 132e of the outermost covering portion 132d is provided below each of the positive electrodes 110 and each of the negative electrodes 120. Note that the peripheral surfaces and bottom surfaces of the multiple positive electrodes 110, the multiple negative electrodes 120, and the separator 130 may be covered with an insulating film (not shown).

[0062] 5 is a cross-sectional view of the secondary battery showing the connection state of the positive electrode tab and the negative electrode tab according to Embodiment 1. FIG. 5 is a cross-sectional view taken along line VV shown in FIG.

[0063] 5, each of the negative electrode tabs 110N is longer than each of the positive electrode tabs 110P. The negative electrode tabs 110N have sagging portions 110T. The negative electrode tabs 110N sag more than the positive electrode tabs 110P.

[0064] Any of the multiple negative electrode tabs 110N includes a sagging portion that is closer to the first wall portion 211 than the third end portion 103 of the electrode body 100.

[0065] Of the multiple negative electrode tabs 110N, the negative electrode tab 110N located on the opposite side (the other side in the second direction) to the swelling direction (one side in the second direction) in which the sagging portion 110T swells is curved in a substantially U-shape. Specifically, the negative electrode tab 110N is curved from one side in the second direction toward the first sealing body 510, and then curves toward the other side in the second direction.

[0066] Of the multiple negative electrode tabs 110N, the negative electrode tab 110N located on the bulging direction side is curved in a substantially S-shape. Specifically, as the negative electrode tab 110N approaches the first sealing body 510 from the electrode body 100, it first curves to bulge toward the other side in the second direction, and then curves to bulge toward one side in the second direction.

[0067] On the other hand, none of the multiple positive electrode tabs 110P protrudes from the third end 103 toward the first wall portion 211 in the second direction (thickness direction T), and none of the multiple positive electrode tabs 110P protrudes from the fourth end 104 toward the second wall portion 212. Of the multiple positive electrode tabs 110P, the positive electrode tab 110P located on the other side in the second direction is curved in a substantially U-shape, first toward one side in the second direction and then toward the other side in the second direction as it moves from the electrode body 100 toward the second sealing body 610. Of the multiple positive electrode tabs 110P, the positive electrode tab 110P located on one side in the second direction is curved toward the other side in the second direction as it moves from the electrode body 100 toward the second sealing body 610.

[0068] In this way, because the multiple negative electrode tabs 110N are longer than the multiple positive electrode tabs 110P, when assembling the first lid assembly 50 to the first opening 215 of the main body portion 210 after assembling the second lid assembly 60 to the second opening 216 of the main body portion 210, it is possible to fix the first sealing body 510 to the main body portion 210 while adjusting the degree of slack in the multiple negative electrode tabs 110N. This makes it possible to prevent the electrode body 100 from being pulled overall to one side in the first direction (toward the first opening 215) when assembling the first lid assembly. As a result, it is possible to reduce the force applied to the electrode body 100, and to prevent the electrode body 100 from being damaged.

[0069] Furthermore, since the negative electrode tabs 110N sag more than the positive electrode tabs 110P, the force applied to the electrode body 100 when the first lid assembly 50 is assembled can be more reliably suppressed.

[0070] Furthermore, since the multiple negative electrode tabs 110N include sagging portions that are closer to the first wall portion 211 than the third end portion 103, a large margin for adjusting the degree of sagging can be secured. This allows for stable electrical connection between the electrode body 100 and the external terminal.

[0071] Furthermore, the positive electrode tabs 110P do not protrude from the third end 103 toward the first wall portion 211 in the second direction, and do not protrude from the fourth end 104 toward the second wall portion 212, thereby reducing the degree of sagging of the positive electrode tabs 110P. This makes it possible to prevent the positive electrode tabs 110P from coming into contact with the housing.

[0072] (Embodiment 2) Fig. 6 is a cross-sectional view of a secondary battery showing a connection state of a positive electrode tab and a negative electrode tab according to embodiment 2. Specifically, Fig. 6 is a cross-sectional view of the secondary battery according to embodiment 2 at a position corresponding to Fig. 5 described above.

[0073] 6, the secondary battery 10A according to the second embodiment differs from the secondary battery 10 according to the first embodiment in that it includes an insulating member 80. The other configurations are almost the same.

[0074] The insulating member 80 is disposed between the sagging portion 110T and the housing 200. The insulating member 80 is disposed between the sagging portion 110T and the wall portion of the main body 210 that faces the sagging portion 110T in the second direction. In the present embodiment, the insulating member 80 fills the gap between the sagging portion 110T and the first wall portion 211.

[0075] The insulating member 80 is provided so as to fit along the sagging portion 110T, and has a support surface 81 that supports the sagging portion 110T. The support surface 81 is, for example, a curved surface that is curved in a U-shape.

[0076] Even when configured as described above, the secondary battery 10A according to the second embodiment has substantially the same effects as the secondary battery 10 according to the first embodiment.

[0077] In addition, the provision of the insulating member 80 can prevent the multiple negative electrode tabs 110N from contacting and becoming conductive with the casing 200. Furthermore, the insulating member 80 has a support surface 81, which can restrict movement of the multiple negative electrode tabs 110N. This can prevent the sagging portion 110T from unintentionally contacting and becoming conductive with the casing 200.

[0078] (Embodiment 3) Fig. 7 is a cross-sectional view of a secondary battery showing a connection state of a positive electrode tab and a negative electrode tab according to embodiment 3. Specifically, Fig. 7 is a cross-sectional view of the secondary battery according to embodiment 3 at a position corresponding to Fig. 5 described above.

[0079] 7, the secondary battery 10B according to the third embodiment differs from the secondary battery 10 according to the first embodiment mainly in the shapes of the negative electrode side conductive member 530 and the positive electrode side conductive member 630. The other configurations are substantially the same.

[0080] The negative electrode side conductive member 530 has a first extending portion 533 that extends in the first direction toward the first end portion 101 of the electrode body 100. The first extending portion 533 is provided at an end portion of the plate-shaped portion 531 that is located on one side in the second direction. The first extending portion 533 has an outer main surface that faces the first wall portion 211 and an inner main surface that is located on the opposite side of the outer main surface in the second direction.

[0081] The multiple negative electrode tabs 110N are connected to the inner main surface of the first extension portion 533. The multiple negative electrode tabs 110N have curved portions that are curved in an overall U-shape. As they extend from the electrode body 100 toward the first sealing body 510, the curved portions first curve toward the side opposite to the side where the first extension portion 533 is located in the second direction, and then curve toward the side where the first extension portion 533 is located. The curved portions form sagging portions of the multiple negative electrode tabs 110N.

[0082] The positive electrode side conductive member 630 has a second extending portion 633 that extends in the first direction toward the second end 102 of the electrode body 100. The second extending portion 633 is provided at an end of the plate-shaped portion 631 that is located on one side in the second direction. The second extending portion 633 has an outer main surface that faces the first wall portion 211 and an inner main surface that is located on the opposite side of the outer main surface in the second direction.

[0083] The multiple negative electrode tabs 110N may be arranged so that none of them protrudes from the third end 103 to the first wall portion 211 side in the second direction (thickness direction T), and none of them protrudes from the fourth end 104 to the second wall portion 212 side.

[0084] The positive electrode tabs 110P are connected to the inner main surface of the second extending portion 633. The positive electrode tabs 110P have less sagging than the negative electrode tabs 110N.

[0085] The multiple positive electrode tabs 110P may be arranged so that none of them protrudes from the third end 103 to the first wall portion 211 side in the second direction (thickness direction T), and none of them protrudes from the fourth end 104 to the second wall portion 212 side.

[0086] Even when configured as described above, the secondary battery 10B according to the third embodiment has substantially the same effects as the secondary battery 10 according to the first embodiment.

[0087] Although the third embodiment has been described with reference to an example in which the first extending portion 533 and the second extending portion 633 are provided at the ends of the plate-like portions 531, 631 located on one side in the second direction, the present invention is not limited to this. The first extending portion 533 and the second extending portion 633 may be provided at the ends of the plate-like portions 531, 631 located on the other side in the second direction.

[0088] (Other variations) In the above-described first to third embodiments, the case where the multiple negative electrode tabs 110N are longer than the multiple positive electrode tabs 110P has been illustrated, but this is not limiting. The multiple positive electrode tabs 110P may be longer than the multiple negative electrode tabs 110N. In this case, after assembling the first lid assembly 50 to the first opening 215 of the main body 210, when assembling the second lid assembly 60 to the second opening 216 of the main body 210, the second sealing body 610 can be fixed to the main body 210 while adjusting the degree of slack in the multiple positive electrode tabs 110P. This makes it possible to reduce the force applied to the electrode body 100 when assembling the second lid assembly 60, and to prevent damage to the electrode body 100.

[0089] Furthermore, in the above case, the multiple positive electrode tabs 110P may sag more than the multiple negative electrode tabs 110N, and an insulating member 80 substantially similar to that in embodiment 2 may be arranged between the sagging portions of the multiple positive electrode tabs 110P and the housing 200.

[0090] In the above-described first and second embodiments, the case where the multiple negative electrode tabs 110N include sagging portions that are closer to the first wall portion 211 than the third end 103 of the electrode body 100 is illustrated, but the present invention is not limited to this. The multiple negative electrode tabs 110N may also include sagging portions that are closer to the second wall portion 212 than the fourth end 104 of the electrode body 100. Even in this case, a large margin for adjusting the degree of sagging can be ensured, and the electrode body 100 and the external terminal can be electrically connected stably.

[0091] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0092] 10, 10A, 10B secondary battery, 50 first lid assembly, 60 second lid assembly, 80 insulating member, 81 support surface, 100 electrode body, 101 first end, 102 second end, 103 third end, 104 fourth end, 110 positive electrode, 110N negative electrode tab, 110P positive electrode tab, 110T sagging portion, 112 positive electrode current collector foil, 114 positive electrode active material layer, 120 negative electrode, 122 negative electrode current collector foil, 124 negative electrode active material layer, 130 separator, 132a interposition portion, 132b first folded portion, 132c second folded portion, 132d outermost coating portion, 132e termination, 200 housing, 210 main body portion, 211 first wall portion, 212 second wall portion, 213 Third wall portion, 214 fourth wall portion, 215 first opening, 216 second opening, 222 pressure release valve, 224 liquid port, 225 sealing member, 510 first sealing body, 520 negative electrode member, 521 negative electrode terminal plate, 522 insulating plate, 530 negative electrode side conductive member, 531 plate-shaped portion, 532 cylindrical portion, 533 first extension portion, 560 insulator, 610 second sealing body, 620 positive electrode member, 621 positive electrode terminal plate, 622 terminal block, 630 positive electrode side conductive member, 631 plate-shaped portion, 632 cylindrical portion, 633 second extension portion, 660 insulator, H height direction, T thickness direction, W width direction.

Claims

1. An electrode body comprising a plurality of positive and negative electrodes arranged alternately in a first direction, and a separator disposed between the positive and negative electrodes, The system comprises a housing for accommodating the electrode body, The aforementioned enclosure is A positive electrode terminal is provided, and a positive electrode side sealing body is positioned at one end of a second direction perpendicular to the first direction, A negative electrode terminal is provided, and a negative electrode side sealing body is located at the other end in the second direction, The electrode body is A positive electrode current collector tab is disposed at one end of the positive electrode in the second direction, The negative electrode includes a negative electrode current collector tab positioned at the other end of the negative electrode in the second direction, The positive electrode current collector tab is electrically connected to the positive electrode terminal via a positive electrode conductive member that is positioned through the positive electrode side sealing body. The negative electrode current collector tab is electrically connected to the negative electrode terminal via a negative electrode conductive member that is positioned through the negative electrode side sealing body. The aforementioned separator is, A plurality of first folded portions are folded back on the outside of the end of each positive electrode in a third direction perpendicular to both the first and second directions, The third direction includes a plurality of second folded portions that are folded back on the outside of each negative electrode end, A secondary battery in which one of the positive electrode current collector tab and the negative electrode current collector tab is longer than the other of the positive electrode current collector tab and the negative electrode current collector tab.

2. The secondary battery according to claim 1, wherein the positive electrode current collector tab is longer than the negative electrode current collector tab.

3. The secondary battery according to claim 2, wherein, as viewed from the third direction, the positive electrode current collector tab and the negative electrode current collector tab include curved portions that, as they move outward in the second direction, move toward one side of the first direction and then toward the other side of the first direction.

4. The secondary battery according to claim 3, further comprising an insulating member disposed on one side of the curved portion in the first direction.

5. The secondary battery according to claim 4, wherein the electrode body is covered with an insulating film.

6. The positive electrode side sealing body is provided with an injection port located on one side of the positive electrode terminal in the third direction, The secondary battery according to claim 5, wherein, when viewed from the first direction, the center of the liquid injection port is located on the side of the third direction that is greater than the end of the positive electrode current collector tab in the third direction.

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